The pectinolytic enzyme of Selenomonas ruminantium.

A cell-bound pectinolytic enzyme was isolated from cells of Selenomonas ruminantium and purified about 360-fold. The optimum pH and temperature for enzyme activity was 7.0 and 40 degrees C. The enzyme degraded polymeric substrates by hydrolysis of digalacturonic acid units from the non-reducing end; the best substrate was nonagalacturonic acid. Unsaturated trigalacturonate was also degraded, but 30% slower than the saturated analogue. The enzyme was classified as a poly (1,4-alpha-D-galactosiduronate) digalacturono-hydrolase; EC 3.2.1.82. Another enzyme, hydrolysing digalacturonic acid to monomers, was also produced in a very small amount by this organism.